Incorrect Arrival Estimates and Arrival Messages


#1

I noticed two things while browsing through the EWR arrivals late tonight, while at the same time tracking the flights on my scanner.

  1. I’ve noticed it before, but looked more closely at it tonight, and it seems the arrival time estimates used here are pretty consistently off by about 5 or more minutes, and always past the actual time. For example, look at the page I viewed here:

http://img221.imageshack.us/img221/3813/flighterrorsth4.jpg

Then, look at when those three enroute flights ended up arriving:

NWA660: 12:54 (actual time around 12:50)
C-GIRE: 12:47 (actual time around 1:02)
UAL974: 1:02 (actual time around 12:58 )

Now, I know a few minutes here and there isn’t that bad, but I’m just bringing it up because it seems to be happening consistently.

  1. While I know the arrival messages received here are controlled by the FAA, it seems the tracking data continues many times after the arrival message is received. For example, look at the C-GIRE flight I mentioned above. Although the arrival message was recorded at about a quarter of, the plane did not touch down until about fifteen minutes later.

This is confirmed through FA’s own tracking page, which can be seen here:
http://flightaware.com/live/flight/CGIRE/history/20061124/0506Z/CYUL/KEWR/tracklog

Since it is obvious FA is still receiving flight data about the plane, isn’t there any way to modify the arrival time to reflect the actual arrival time, or to ignore the erroneous arrival message?

Just a few thoughts to ponder.


#2

Agree on #2. Regarding #1, see flightaware.com/about/faq.rvt#wrongtime – it’s intentional.


#3

You see, this is where I start getting a bit confused. The data is delayed by about 5 minutes, but looking at the times recorded in the track log, the time stamps appear to be the correct times. Because of this, if you used these times, you would not need to add 5 addition minutes. Am I missing something?


#4

If we displayed the ETA and time remaining as the accurate ETA, every flight would go into “0 minutes remaining” and arrive 5-6 minutes late.

Accordingly, we add 6 minutes to ETAs and then retroactively mark the correct arrival time. So, you’ll see the ETAs to be 6 minutes in the future and the “two minutes remaining,” for example, indicates how long until we project it will be until we can say it’s arrived. Then, we will mark the correct arrival time and it will be in the past.


#5

Ok, I understand the reasoning now, thanks for the explanation.